CONTEXT: The impact of dietary protein on body composition changes after older adults purposefully lose weight requires systematic evaluation OBJECTIVE: : This systematic review and meta-analysis assessed the effects of protein intake (< 25% vs ≥ 25% of energy intake or 1.0 g/kg/d) on energy restriction-induced changes in body mass, lean mass, and fat mass in adults older than 50 years. DATA SOURCES: PubMed, Cochrane, Scopus, and Google Scholar were searched using the keywords "dietary proteins," "body composition," "skeletal muscle," and "muscle strength." STUDY SELECTION: Two researchers independently screened 1542 abstracts. DATA EXTRACTION: Information was extracted from 24 articles. DATA SYNTHESIS: Twenty randomized control trials met the inclusion criteria. CONCLUSION: Older adults retained more lean mass and lost more fat mass during weight loss when consuming higher protein diets.